1. Field of the Invention
The present invention relates to an image capturing apparatus and an image display method, and in particular, relates to an image capturing apparatus and an image display method which are suitable for obtaining a wide-angle image and a telescopic image simultaneously and for displaying both images on a display in a finder.
2. Description of Related Art
Conventionally, in image-inputting apparatuses, e.g., video cameras and digital cameras, a zoom function is commonly used for varying focal lengths, i.e., perspective angle of a lens in view of a distance between the camera and an object to be captured, in order to magnify and reduce image size. In order to prevent failure in capturing the object, a camera must have a finder visualizing an image corresponding to a desirable perspective angle. Generally, the zoom function can be categorized into an optical zoom which is realized by moving lenses contained in a lens unit mechanically; and an electronic zoom which is realized by interpolating new pixels between pixels generated based on image data output from an imaging device, e.g., a charge-coupled device (CCD).
Since the image obtained by the optical zoom has a desirable perspective angle in the finder, it is not necessary to conduct image processing operation because both the image obtained in the finder and the image to be captured by the zoom lens will not be deteriorated.
In contrast, since the electronic zoom is realized by conducting the image processing operations with respect to the image obtained through an optical system. In this case, mechanical focusing is not necessary if the perspective angle is varied by the electronic zoom function. Therefore, the electronic zoom is advantageous due to its quickness. Multi-display image capturing devices which can display through-images corresponding to various magnifications have been proposed in order to realize such advantage obtained by the electronic zoom (see, e.g., Japanese Unexamined Patent Application, First Publication No. 2004-200950). In this device, images of an object corresponding to a plurality of perspective angles are displayed on a finder by an electronic zoom function, and an image of the object is captured by selecting a composition corresponding to a desirable perspective angle, i.e., focal length using an optical zoom function. This device has advantages, e.g., finding the object before capturing the image thereof in a desirable composition; and capturing the image quickly.
In general, a main object is commonly disposed in a central portion of the captured image. In such a case, in order to display a telescopic image in the finder by the electronic zoom function, a central portion of the image corresponding to the telescopic image as shown in FIG. 16B must be trimmed from a wide-angle image shown in FIG. 16A. In addition, the perspective angle of the trimmed telescopic image must be adjusted to a display area in the finder by interpolating pixels corresponding to image data of the trimmed central portion.